The objective is to understand the role of the mechanical (elastic-fluid) activity of the cochlea in the transformation of sound into receptor cell stimulation. Recent preliminary calculations for a model with an "organ of Corti", "tectorial membrane" and "inner sulcus" show in the linear response that the pressure in the inner sulcus is larger by a factor of 10 than that in the scali. The full consequence of this unexpected phenomenon will be determined. In particular, the nonlinear effect of lifting the tectorial membrane from the inner hair cell cilia must be of significance at high sound intensity levels, and possibly also at moderate levels. Effectiveanalytical means of including such a nonlinearity with the response of the basilar membrane will be obtained. In addition, studies will continue on the effect of gross cochlear anatomy, such as primary and secondary osseous lamina construction, coiling and taper.